UC flame-retardant study finds risk for kids

UC BERKELEY

Marla Cone, Environmental Health News

Published 4:00 am, Wednesday, April 20, 2011

A new UC Berkeley study found Mexican American children from the Salinas Valley are contaminated with levels of flame retardants seven times higher than children in Mexico and three times higher than their own mothers.

The 7-year-olds had higher levels than almost all other adults and children tested worldwide. Household dust, which is contaminated with flame retardants released by old furniture, is probably the major source of their exposure.

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The researchers cautioned that while their study focused on California children, it has nationwide importance because flame retardants are used in furniture sold across the country.

Health effects of the chemicals are largely unknown, but two studies have linked them to reduced motor skills and cognitive abilities in children, as well as declines in fertility.

The findings suggest that low income, rather than race, is probably the major factor in determining who is highly exposed to brominated flame retardants. Poorly manufactured or deteriorating furniture may release more of the compounds, which are added to polyurethane cushions to slow the spread of flames when furniture catches fire.

Intake of house dust

The only people with higher levels of the flame retardants in their bodies were children in Nicaragua living or working on hazardous waste sites, according to the study, which was published online in the scientific journal Environmental Health Perspectives.

"My first reaction is surprise, then the thought that we believe intake is mostly from dust, soil and food," said Schecter, who has studied flame retardants in the food supply and environment but did not participate in the California study. "Higher intake of house dust would be expected from a rural, poor population."

Schecter added that food also is a source. The flame retardants have been found in many foods, particularly fish, meat and dairy products.

The new study found that the California children are more highly contaminated than any adults, and more contaminated than Mexican children and Mexican American children living in other states.

The high exposures of California children "may be an unintended consequence of government regulation," the authors said in their study.

Large volumes of PBDEs, or polybrominated diphenyl ethers, have been used in the United States, particularly in California, to meet a state flammability standard for furniture adopted in the 1970s. Furniture foam sold in California must withstand 12 seconds of flame without catching fire.

Children more susceptible

Tests have found seven to 10 times more brominated flame retardants in the dust of California homes than dust of homes elsewhere. The highest levels were found in Oakland and Salinas homes.

"Scientists know that when you have persistent pollutants in dust, they get into children," said UC Berkeley environmental health scientist Asa Bradman, a co-author of the study. Children play on the floor and have more hand-to-mouth contact to the dust than adults.

The new study was conducted on a group of Salinas Valley children who have been studied by the Berkeley scientists since birth.

Blood samples of 264 Mexican American children born and raised in the Salinas Valley were compared with tests of 283 children in Mexico, including three regions where most of the Salinas Valley mothers emigrated from. The team also had tested the blood of the California children's mothers before the children were born, when they were 26 weeks pregnant.

The concentrations of the flame retardants were on average three times higher in the children than they were in their pregnant mothers.

For all types of PBDEs, "children born in the U.S. had significantly higher levels than children born in Mexico," the authors wrote. The longer their mothers were in the United States, the higher the child's concentrations.

Penta phased out nationally

One of the most persistent and abundant compounds, called penta, was banned in California and phased out nationally in 2004. Newer flame retardants have taken its place, but the Berkeley researchers warned that little is known about their risks.

"The health consequences of these chemical replacements should be investigated and weighed against their purported fire safety benefits," they wrote.